Suction felter apparatus and method



June 14, 1960 c. c. HERITAGE 2,940,135

SUCTION FELTER APPARATUS AND METHOD Filed Jan. so. 1953 2 Sheets-Sheet 16U. fforney June 14, 1960 c. c. HERITAGE 2,940,135

SUCTION FELTER APPARATUS AND METHOD Filed Jan. 30. 1953 2 Sheets-Sheet 2WWW Unitccl States Patent SUCTION FELTER APPARATUS AND METHOD Clark C.Heritage, Tacoma, Wash., assignor, by direct I and mesne assignments, ofone-half to Weyerhaeuser Company, a corporation of Washington, andone-half to Wood Conversion Company, St. Paul, Minn., a corporation ofDelaware V Filed Jan. 30, 1953, Ser. No. 334,163

20 Claims. (Cl. 19-156) The present invention relates generally to theproduction of air-laid felts and apparatus therefor, and in particularto pneumatic apparatus having independently controlled air-pressure andair-suction systems inter-connected through the atmosphere at a regionwherein the felt is formed.

The present invention is a continuation-in-part of my copendingapplication Serial No. 182,965, filed September 2, 1950.'

Among conventional ways to form air-laid fiber felts are deposition bygravity from dispersion in air, and deposition by filtration from amoving suspension in air. In deposition-by gravity, fibers land onfibers with such a low impact that they form a mass more like a pile offibers than a felt of fibers. When the impact at deposition isincreased, each fiber tends to penetrate deeper into the mass of fiberson which it lands, and also to compress the mat being formed to adensity in equilibrium with the forces predetermining the value of theimpact. Impact is commonly made relatively high by filtering a stream ofair in which the fibers are suspended, using the felt already depositedas the exposed part of the filter. In forming a continuous mat byfiltration on a moving mechanical filter, the exposed surface of thefilter varies from that of the mechanical filter itself at one extremeto that of the deposited mat at the other extreme. This variationcommonly involves difficulties with respect to uniformity from face toface. i

The density and uniformity of formation in a mat as felted are importantwith respect to the density and uniformity of structure when that mat'is compressed to a uniform thickness. In making densehot-press'ed boardfrom such' mats, final uniformity of density is very important, anddeviations are'manifest in "the appearance and character of the board.The lower the density of the initial mat or felt, theless a givendifferential in its thickness is reflected in variation of boardproperties; w

It is desirable to make the initial mat as uniform as possible in all ofits characteristics, and then to'cornpress either to handleability or toa useful article of commerce. However, to do so involves difiiculties.

In air-laid felts, the strength depends upon the interlocking of fibers.In compressing an initially deposited mat in horizontal position,vertical fibers therein tend to move toward the horizontal position. Tothe extent that the initial density is greater, such vertical fibers,herein called nailers, on compression hold or catch more of theremaining fibers both under them and over them for added strength. Tothe extent that the initial density is less, the nailers on compressiontend to lie in layers with other fibers, yielding a compressed matexhibiting cleav- 2,940,135 Patented June 14, 1 960 area. The presentapparatus is especially suitable for producing such nailer-strengthenedmats. As the moisture content of the fibers increases, the fibersdeposit with greater impact under a given set of conditions.

It is a general object of the invention to provide discharging apparatusfor air-suspended fibers.

It is a general object of the present invention to provide an air-layingfelter in which fibers are felted to a mat of substantially uniformdensity and thickness, in a region exposed to the atmosphere on acontinuously moving conveyer, and at a relatively rapid rate.

It is a particular object to provide a depositing region exposed to theatmosphere in which an air stream carrying fibers to the region iscontrolled, and in'which a second air stream feed from the felted fibersis independently controlled and in which the second air stream Withinthe said depositing region may be advantageously locally com trolled.

It is another object of the invention to control the character of eitherone or both of the exposed faces of the felt by the relationship betweenthe two controlled air streams, and by other means.

It is a particular objectof the invention to form a thick mat and bysuitable control to effect mailer-forming impact on deposition, andadditionally to provide substantially the same kind of formation at thefirst-formed layer, the last-formed layer, and the intermediate layers.

Various other and ancillary objects and advantages of the invention willbecome apparent from the following description and explanation of theinventiomas described with reference to-the accompanying drawings inwhich:

Fig. 1 is a diagrammatic representation of the felter and various partsfunctioning therewith.

Fig. 2 is a plan view of a portion of the apparatus shown in Fig. 1 toillustrate particularly the alinement of certain parts. 7

Fig. 3 is a detailed view in vertical cross-section showing theprincipal features of the felter.

The drawings show a preferred embodiment of the invention, but it is tobe understood that component parts within the scope of the appendedclaims may be used in other combinations. I

The illustrated apparatus provides a moving foraminous conveyer on whichthe felt is formed substantially at atmospheric pressure in a regionover a suction box. A perforated dispersing head contains a stock ofagitated fiber at superatmospheric pressure, which stock is contimiouslyreplenished and drawn ,upon. A constant stream of air passes through thehead and in so doing sweeps individual fibers from the head and into thedeits axis crosswise of the moving conveyer is ideal to meet theseconditions. To maintain some degree of order in the agitation, aconstant speed mechanism is used for agitation, and where this is acoaxial rotor it preferably revolves in such a direction that itmaintains a constant uniformity of turbulence axially within the head.This relationship is hereinafter described.

The air-pressure in the head causes a leaving current of air to carryindividual fibers speedily away from the head into a depositing regionwhere the felt is formed. This region is 'expo'sedto the atmosphere,thus eliminata,94.o,1s ,1 I

ing need for a closed housing which is required if the felt is formed atother than atmospheric pressure. The depositing region is defined bypassing a continuously moving filter, such as a wire screen, over anarea mamtained at subatmospheric pressure, and placing the disperse inghead in spaced proximity to the suction area and substantially entirelywithin its sphere of influence in operation as described.

The pressure in the head and the suction below the screen are so relatedthat a continuous and constant stream of air carrying fibers passesthrough the atmosphere to the depositing region and is there filtered toform the felt. By providing two independentlycontroh lable pneumaticsystems interconnected throughethe at= mosphere at the depositingregion, many factors in mat formation may be controlled, when the areaof the suction box is so located as to comprehend the stream from thedispersing head. I

When each system carries the same amountof air, there is theoretically aperfect balance. But the suction system may be adjusted to carry more orless air than the pressure system, with special advantages in each case.Because the moving forming mat adds increasing resistance to-air fiowfrom one end of the depositing region to the opposite end, there may beimposed a compensating and variable mechanical resistance, therebytending locally to equalize the fiow of air carrying the fibers to thescreen. As described hereinafter, this may be effected by placing underthe screen at the opening of the suction box, numerous plates, variouslyperforated, or

even imperforate where it is desired that an edge of the depositingregion be moved inwardly from the, edge of the suction box.

These objectives are all readily efiected by the apparatus shown in thedrawings. In Fig. 1 there is provided an endless wire screen 10 betweenend rolls 11 and 12, at least one of which is rotated at a constant butcontrollable speed. A master control means 13 is indicated, havingrelation to other parts, and having its relation to the moving screenrepresented by the dotted. line 14 to roll 11. A constant voltage powersource coupled with proper motors may serve as the master control means13. The screen 10 preferably moves in a horizontal plane and traverses adepositing region 16 over a suction box 17 located below the upperstretch of the screen 10. The suction box is connected by conduit 18 tothe intake of a suitable blower 1 9 The blower 19 is arranged to,operate at a regulatable constant speed by means having a relation toother parts through the control means 13.

Over the depositing region there is a fiber disperser generallydesignated 22, with air therein maintained at super-atmospheric pressureby a suitable means such as a connection through a conduit 23 to thepressure side of a suitable blower 24, of which the inlet is connectedby conduit 25v to a region atatmospheric pressure, and preferably tofiber-receiving hopper 26. Blower 2.4, is operated at a constant butcontrollable. speed by. means indicated at 27 having relation to otherparts through other parts of the general assembly are described; The

fiber-receiving hopper 2 6 is shown as receiving a CQHtiBUn ous chargeof fibers 3}} to be dispersed for feltingl The fibers 30 arecontinuously fed into the hopper at a constant rate by suitable controlmeans. To illustratea suitable control the fibers 30 are shown as beingdischarged from a moving endless belt 31' running on two rolls 32 4 and33, and receiving fibers in a stream 34. When the axis of roll 33 isfixed and roll 32 floats in a balanced condition, as against tensionspring 35, the assembly may be used as a volume or weight regulator ofstream 30: Such devices are well known. The one herein describedoperates by the weight of fibers 36 carried on upper stretch of belt 31,causing the roll 32 to move and adjust its vertical position. Themovement is used to vary the rate of supply of fibers in stream 34 byknown means (not shown).

Sometimes, more than one material is fed into the hopper 26 forincorporation into the felt. It may be a second kind of fiber, or it maybe a binder in solid form such as a powdered thermosetting resin. Whenit is such a resin, other features of the apparatus become important.Numeral 40 represents a supply of such resin at a constant rate from acontrolling belt 41, which may be part of a regulator such as thatsupplying fiber 30.

Many materials felted by suction provide a fraction of fines that escapethe felting process and pass through the filter. The quantity of theescaping fraction is often appreciable and is often ofsignificantimportance particularly' in the case where a powdered ingredient ispresent, such as a resin binder. Although it is important for economicreasons to recover such escaping fines, it is also important to do sofor other reasons. Where two materials, such as fiber 30 and resin 40are supplied at fixed rates, they exist and mix at fixed proportionsprior to felting, and are naturally proportioned according to theproportion desired in the felt. When this proportion is disturbed by adisproportionate escape of fines, the effect may be corrected in acontinuous oper ation by returning all the fines to the felter.

For such purposes, numerous expedients are. possible. For example, theexhaust of suction-side blower 19- is connectcd by conduit 43 to asolids-separator, such as separating cyclone 414, which is shown asreturning a constant stream of the recovered, fines 45 to the hopper 26.Because the fines 45 have been, previously and initially weighed in,they pass directly into the hQpper 26. The cyclone 44. is shown asdischarging air to the atmosphere at its vent 46. Where a thermal orother economy factor is involved, a partat least; of; the airlost atexhaust- 4'6 may bev reused in feeding air into conduit 25, by knownmeans not indicated. These'econornics are described in my earlierapplication Serial No. 182,965,, filed September 2, 1950, of which thepresent application is'a continuaiQn-in-Part. v

Fig. 2, is a plan view of; the felter, to. which attention isdirectedfor features, directly connected with the. dis perser shown in detail inFig. 3,. Where fiber is, introduced into the dispersing head byentrainment in, the air supplied thereto, certain conditions must. beavoided and others observed, to maintain uniformity of fiberdistribution in the dispersing head crosswise of the moving 'conveyor.To these ends the conduit 23 and the periphery of the blower 24 arealined with the direction of movement of the felting screen 10, as; ondotted line 50, which is an axis of symmetry for; the, disperser and,for depositing region16. Fig. 2 shows initially a, formed mat- M leavingthe depositing region.-. It has vertical lateral edges 51 and 52 ,byreasonofitsformation, against't'wo parallel vertical side plates 53 and54, later described. The initiallyjformed mat M may be, insufficientlyfeltedi to be handled, apart from, its original horizontal support.There,- fore, itmay be compressed to, greater density in, one. or morestages of compression, of which one, stage is indi cated by a pairofrolls 55 and, 56, forming. pressed mat P to facilitate removal from thescreen 10. The compression may widen the mat as shown by new edges, 51and 58, unlessopposing bafile plates, are used. If necessary, suchextended edges may be trimmed forming new vertical edges58 and,59-andfwaste 60.,

The described alinement, of, conduit23, and, its, blower 1 -18, a. mtter of great. import nce. Centrifugal. action in blower 24 loads theair stream conduit 23 more at the region 61 than opposite it at region'62. Equalizagooseneck 64 again introduces a centrifugal force. whichthrows a heavier concentration of fibers and the heavier componentsthereof more toward the front wall 67 of housing 66 than rearwardly ofit.

The housing 66 is an expansion conduit for the fiber-air suspensionconveyed in conduit 23. It serves to reduce the velocity so that theimpact of conveyed fibers on being arrested in thehousing minimizesfelting in the housing. It also serves to equalize the air stream overthe area discharging to the atmosphere. Since the latter dischargingarea requires straight sides parallel to the axis line 50, and.substantial identity of crosswise conditions between such sides andalong every intervening parallel line, the discharging area must berectangular in its horizontal projection. Accordingly, the housing 66fiares generally downwardly through increasing rectangularcrosssections. For. simplicity and economy, this is preferably done by apyramidal type of structure. 1

As illustrated and as used in one studied embodiment of the invention,the housing 66 flares with a rectangular nated 80, co-axialwith head 72,having end disks 81 and spaced bars lying in a cylindrical arrangement,such as the elemental bars 82, preferably carrying bristles 83 to brushfibers through the perforations. The agitator must be designed to avoidlateral urging of fiber stock, in order to maintain crosswiseuniformity. For example, spiral bars, like those on a lawn mower cutter,would move the stock along its axis. The rotor turns at a high speed, asin a range from 175 to 600 r.p.m. Its direction is such as to cause thefibers which move with it to mesh with the heavier feed of fibers downthe front wall 67 of the housing 66. Thus, where the conduit 23approaches fromthe right in Fig. 3,.the agitator operates best whenturning counter-clockwise in Fig. 3.

The air rushing through the holes 74 carries fibers with it as indicatedby numeral 85. The path ofvfibers 85 is predetermined largely by asuction area under screen 10 and by positioning bafiles, such as theside plates 53 and 54 or others. For example, there is shown a rearvertical baffle 86 extending nearly to the screen 10, but forward of therear edge 87 of the suction box 17. To the extent desired, suction mayextend rearwardly from baffie 86.

The lower edge of baffle 86 may be so high and the suction at'saidedgebe so reduced that a stream of the lighterweight or fine fibersdesignated 88 may float out and deposit first on the screen 10 topredetermine the texture of that face. The mat M begins toformsubstantially at the junction of bafile 86 and screen lih'wheresuction funccross-section from a top opening of about 9 x 18 inches to abottom opening of about 24 x' 54 inches in a vertical drop of about 17feet. These dimensions are merely illustrative. Its walls are designatedclockwise in Fig. 2 as-67, 68, 69 and 70. For uniformity crosswise ofthe housing, the periphery of blower 24, and all of conduit 23 includingits gooseneck 64- lie in a vertical plane which bisects every'horizontalcross-section offthe housing about midway longitudinally of theconveyor.

. v The bottom opening of the housing 66 may have a terminal dispersinghead or it may be extended by a suitable tubular means, such as aprismatic 'box-like section 71 with four vertical side walls, foranysuitable or desired distance, for example about 5: feet. Therectangular bot.-

tom opening of the housing 66 as extended by section 71 is closed by aperforated head, preferably a semi-cylindrical dispersing head-72Iwithits horizontal axis 73 at right angles to axis line 50. The box 71 isshown as telescopic in twosections to permit adjusting the verticalheight of the dispersing head 72 above thescreen 10.

arc, of about 100 of the periphery is perforated substantiallysymmetrically of line 50 with holes 74 of size to effect substantialindividualization of the ,fibers con- In the case of 'stituti ng thecharge fed .to blower 24. .wood fibers 30 previously liberatedsubstantially as individualized ultimate fibers of the wood, the holesmay be 91 inch in diameter and countersunk deeply from the exteriorside. The countersinking minimizesthe extent of cylindricalwall in thehole and thus minimizes the tendency of the holes to plug and to deliverslugs felted within thehole. The more numerous the holes, the greaterthe capacity of the system. A wide variety of hole sizes, shapes andarrangements is permitted. In one form the holes have been alined alonggeometrical elements of the head 72 on half-inch centers, staggered inadjacent rows, and said rows spaced on 0.4375 inch centers. Afiexibleadjustable gate 75, like the closure of a roll-top desk, is positionedto vary the effective are of perforations.

In Fig. 3 the arrows 76 in housing 66 indicate the downward course offibers and air and a heavier concentration of fibers along the frontwall 67. Numeral 77 7 tained in agitationby suitable means. This isdesigned to minimize the formation of obstructive fiber clots. Preftionsat the line of halide 86, building up on an incline to the finalthickness of mat M. The density and thickness of the initial mat may bevaried over wide ranges by control of the materials and operatingconditions. For example, where wood fiber with a few percent of addedresin binder is to be formed into hot-pressed board ata density of 64pounds per cu. ft., and in thicknesses of inch, the initial mat may havea density in the range from 2 to 6 pounds per cu. ft. ,ofoven dry fiberat corresponding thicknesses in the range from 8 to 2.7 inches. Theseresults may be achieved with a pressure in the headof 0.1 to 1.0 inch ofwater, and a suction in the box 17 of about 2 to 30 inches of water,under the following described conditions of graded partial obstructionof'the area of suction. For the dispersing head having the dimensionspreviously given above, the volume of delivery air may vary roughly inthe range from 1000 to 5000 cu. ft. per minute.

A planar incline for the forming top surface of the mat signifies evendistribution of fibers over the depositing area, and hence substantiallyuniform impact'on deposition. Were the suction box 17 open directly tothe screen, the greater volume of air, and hence concentration of fiber,would obtain at near the bafile 86, and the resulting mat would soresist the suction as to maintatin this unequality of distribution.Accordingly, the suction is controlled and distributed to secure aplanar incline to the forming top face of the mat.

The preferred means to distribute the suction is to employ .an openconstruction for the suction box 17 and to provide for it changeableplates together forming a functioningcover for the open top in themanner setforth in Roberts U.S. Patent No. 2,912,723: Numerous plates ofwhich the length of each runs crosswise of and under the screen 10,provide a suction platform over which the screen 10 runs. Perforationsmade in the plates determine the effective boundaries of the depositionregion 16. Uniformity requires the perforations to be uniform crosswiseof the screen, and build-up of the mat calls for variation lengthwise ofthe screen. The perforations in their effective area increase forwardlyof the machine, and are arranged with respect to particular conditionsand materials, having as an objective the creation of the inclined plane89 for the growing face of mat M. V

As shown, rear plate 90 is a blank or closure plate, cutting ofifsuction to the rear of halide 86, except for erably, it is asquirrel-cage-type of rotor generally desigsome perforations 91 in theforwardly adjacent plate The most forward plate 90 is shown, also as ablank. To its rear the adjacent plate 90 is more perforate than therearinost'perforate plate 90' to compensate for the resistance of thethicker mat formed above it. The region between pl'ates 90 and 90* hasplates with perforated area increasing from that in plate 90 to that inplate 90".

As shown in Fig. 2 the side plates 53 and 54 lie vertically alongsidethe ends of the semi-cylindrical head 72, and the suction plates havetheir perforations extending to but not beyond the said side plates.Side plates 53 and 54 preferably have lengths at least comprehending theregion between the forward and rearward edges of suction box 17. Sideplate extension along theentire length of the uncompressed web isundesired because of possible drag and dislocation of fibers at thelateral edges. In. practice, when the suction 'systemis operated atgreater capacity for ,air than the fiber-feeding system, an

' envelQPfii ofair from the atmosphere is drawn in, to house all themoVing'fiber, provided the plates are suitably perfor'ated at theforward and. rearward edges. This .is xzery desirable where the fibermay contain dust, or an expensive or a dangerous ingredient, desirablynot wasted into the atmosphere.

However, as shown, the relative capacities of the two blowers, or thearrangement of the suction plates, may be so chosen that at the forwardend over mat M there is a forward winnowing of air from the head tocarry lightweight fine fibers for final deposition, as indicated at 92.The air so permitted to move forward may drop its fines by gravity anddiffuse into the atmosphere, or it may respond to a slight suction inthe mat M resulting-from suitably limited perforations in the forwardplates.

The apparatus may be operated over a wide range of conditions for itsnumerous variables in order to achieve different predetermined elfects.The superatmospheric pressure in the head is preferably muchless'in-degree than the subatmospheric pressure in the suction box,largely because of theresistance to air passage imposedbyithe. mat beingformed. Suitable operating ranges are from 0.1 to -1 .0 in'chof water aspositive pressure, in the head and from '1 to 30 inches of waternegative pressure in the suction box.

In one particular study of such variables, the following spans withingreater ranges have been covered:

Delivery air:

Static pressure in V head -2 -6 inch-of'water. Volume 2460 to 3570 cu.ft. per minute.

Suction air:

Negative pressure in boxv Volume Volume ratio of suction: Airto deliveryair 0;88 to 1.22.

a All of the above are directed to conditions for producing pressedboards of A; inch thickness at 64 pounds per cu. ft.

The invention is not limited to the entire assembly as illustrated. Thedispersing head is disclosed as vertical because of its use to depositfibers on a horizontal conveyer; The multiplicity of jets of aircarrying fiber, as discharged from the head may be moved in directionsother than vertical, for example by turning the assembly of expansionchamber-and head to a horizontal position, and using the same as adisperser for other uses of the fiber, .or for other means of felting.

From. theforegoing it will be appreciated that the appst tusisambled-modification torqmanykiads of fibers,

4.18 to 7.38 inches of water. 2550 to 3940 cu. ft. per minute.

and for operation in many combinations of variable factors, .to producea wide variety of felts.

1. Apparatus for felting comprising a movable endless screen on whichcontinuously to form a fiber felt at a stationary deposition areathereof exposed to the atmosphere, means providing suction under saidscreen and thereby defining said deposition area, a blower having itsinlet connected to said suction means and its outlet arranged todischarge into a region at atmospheric pressure, an expansion housingflaring laterally in all directions toward said deposition area, aperforated head for passing substantially individualized fibers closingsaid housingand located inspaced proximity to said deposition area,means/to maintain agitation of fibrous material in the vicinity oftheperforations of said head, a second blower having its inlet connectedtodraw air frolna region ataatmospheric pressure and its, outletconnected to the small end of saidfiaring housing whereby to createsuperatmospheric pressure in said head, means continuously to feedfibers for entry into said head for dispersion therefrom, means to movesaid screen, and means to increase the degree of suction in saiddeposition area in the direction of movement of said screen.

2. Apparatus for felting comprising a movable endless screen on whichcontinuously to form a fiber felt at a stationary deposition area.thereof exposed to the atmosphere, means providing suction under saidscreen and thereby defining said deposition area, a blower having itsinlet connected to saidsuction means and its outlet arranged todischarge into a region at atmospheric pressure, an expansion housingflaring laterally in all directions toward said deposition area, aperforated head for passing substantially individualized fibers closingsaid housing and located in spaced proximity to said deposition area,means to maintain agitation of fibrous material in the vicinity of theperforations of said head, a second blower raving its inlet connected todraw air from a region at atmospheric pressure and its outlet connectedto the small and of said flaring housing whereby to createsuperatmospheric pressurein said head, means continuously to feed fibersfor entry into said head for dispersion therefrom, means to move saidscreen, and variably perforated 3. Apparatus for felting comprising arectangular X I pansion conduit flaring downwardly in bothcross-sectional dimensions, means 'to' feed into the top of, said'conduit at superatmospheric pressure a suspension air of materialincluding" feltable fibers, a semi-cylindrical head closing the lowerend of Said conduit and exposed externally to the atmosphere, a portionof said head between two geometrical elements thereof being perforatedfor the dispersal of and passage of said material therethrough, a rotorin. said head provided with fiber-agitating members and arranged inrotation to distribute said material'for dispersal through saidperforated portion, a movable endless foraminous felting conveyor spacedbelow said head and arranged to travel horizontally under said head in aforward direction transversely of theaxis of the head, independent meansto exert suction on the under side of said conveyer over an areaincluding the projected area of said perforated portion of the head andextending both rearwardly and forwardly of said area, spaced verticalside plates closing the lateral space between said conveyor and saidhead for defining the width of a Web to be felted therebetween, thecapacity for suction being such as to take in substantially more thanthe amount of air fed to said head, whereby in operationfibers aredischarged from the head substantially uniformly in concentration inelemental directions along the: head and ,felt

on the conveyor and on the felt'being iormedthereon and are thereon firmy hel by he p ssing air stream g ns movement from. the lin -of.deposition thereon.

, '4. Apparatus forv felting comprising a rectangularex! pansion conduitflaring downwardly both cross-sectional dimensions, means to feed intothe top of said conduit at superatmospheric pressure a suspension in airof material including feltable fibers, a semi-cylindrical head closingthe lower end of said conduit and exposed externally. to the atmosphere,a portion of said head between two geometricalelements thereof beingperforated for the dispersal of and passage of said materialtherethrough, a rotor in said-head provided with fiber-agitating membersand arranged in rotation-to distribute said material for dispersalthrough said perforated portion, a movable endless foraminous feltingconveyer spaced below said. head and arranged continuously to travelhorizontally under said head in a forward direction transversely of theaxis of the head, independent means to exert suction on the underside ofsaid conveyer over an area including the projectedarea of saidperforated portion of thehead and extending both rearwardly andforwardly of said area, the capacity for suction being such as to takein substantially more than the amount of air fed to said head, wherebyin operation fibers are discharged from the head substantially uniformlyin concentration in elemental directions along the head and felt on theconveyer and on the felt being formed thereon and are thereon firmlyheld by the passing air stream against movement from the line ofdeposition thereon.

5. Apparatusfor felting comprising a rectangular expansion conduitflaring downwardly in ,both cross sectional dimensions, means to feedinto the top of said conduit at superatmospheric pressure a suspensionin air of material including fel-table fibers, a semi-cylindrical headclosing the lower end of said conduit and exposed externally to theatmosphere, a portion of said head between two geometrical elementsthereof being perforated for the dispersal of and passage of saidmaterial therethrough, a rotor in said head provided withfiber-agitating members and arranged in rotation to distribute saidmaterial for dispersal through said perforated portion, a movableendless foraminous felting conveyer'spaced below said head and arrangedcontinuously to travel hori zontally under said head in a forwarddirection transversely of the axis of the head, independentmea'ns toexert suction on the underside of said conveyer over an area includingthe projected area of said perforated portion of the head and extendingboth rearwardly and for! wardly of said area, spaced vertical sideplates closing the lateral space between said head for defining thewidth of a web to be felted therebetween, and means to regulate thedegree of suction locally so asto increase it in the die rection ofvmovementof the conveyer, the capacity for suction being such as to takein substantially more than the amount of air fed to said head, wherebyin operation fibers are discharged from the head substantially uniformlyin concentration and formation in' elemental directions along the headand felt with controlled impact on the coveyer and on the felt beingformed thereon and are thereon firmly held by the passing air streamagainst m'dvementfrom the line of deposition thereon.

6. Apparatus for felting comprising a rectangularexpan'sion conduitflaring downwardly in both cross-sectional dimensions, means to feedinto the top of said conduit at superatmosphericpressure a suspension inair of material including feltable fibers, a semi-cylindrical headclosing the lower end of said conduit and exposed externally to theatmosphere, a portion of said head between two geometrical elementsthereof being perforated for the dispersal of and passage of said material therethrough, a rotor insaid head provided with fiber-agitatingmembers and arranged in rotation to distribute 'said material fordispersalthrough said perforatedfportion, a movable endless foraminousfelting conveyer spaced below said head and arranged continuously totravel horizontally under'said headin a forward direc- '10 means toexertsuction 0n the underside of said conveyer over an area including theprojected area of said perfo ratedportion ofv the head and extendingboth rearwardly and forwardly of said area, and means to regulate thedegree of suction locally so as to increase it in the direction ofmovement of the conveyer, the capacity for suction being such as to takein substantially more than the amount of air fed to said head, wherebyin oper-. ation fibers are discharged from the head substantiallyuniformly in concentration and formation in elemental directions alongthe head and felt with cotrolled impact on the conveyer and on the feltbeing formed thereon and are thereon firmly held by the passing airstream against movement from the lineof deposition thereon.

7. Apparatus for felting comprising a rectangular expansion conduitflaring downwardly inboth cross-sec- .tional dimensions, means to feedinto the top of said conduit at superatmospheric pressure a suspensionin air of material including feltable fibers, a perforated rectangu-'lar head closing the lower end of said conduit and exposed externally tothe atmosphere, the perforations being arranged for dispersal ofsubstantially individualized fibers therethrough uniformly in one of itstwo rectangular di-' mensions, agitating means in said head todistribute said material for dispersal through said perforated head, amovable endless foraminous felting conveyer spaced below said head andarranged continuously to travel horizontally under said head in aforward direction transversely of said one dimension, independent meansto exert suction on the underside of said conveyer over an .areaincluding the projected area of said perforated portion of the head andextending both rearwardly and forwardly of said area, spaced verticalside plates closing the lateral space betweensaid conveyer and said headfor defining the width of a web to be felted therebetween, the capacityfor suction being such as to take in substantially more than the amountof air fed to'said head, whereby in operation fibers are discharged fromthe head substantially uniformly in concentration along said onedimension of the head andjfelt on the conveyer and on the felt beingformed thereon and are. thereon firmly held bythe passing air streamagainst movement from'the line of deposition pansion conduit flaringdownwardly in both cross-sectional dimensions, means to feed into thetop of 'said conduit at superatmo'spheric pressure a suspension in airof material including feltable fibers, a perforated rectangular headclosing the lower end of said conduit and exposed externally to theatmosphere, the perforations being arranged for dispersal ofsubstantially individualized fibers therethrough uniformly in one of itstwo rectangular dimensions, agitating means in said head to distributesaid material for dispersal through said perforated head, a movableendless foraminous felting conveyer spaced below said head and arrangedcontinuously to travel horizontally under said head in a forwarddirection transversely of saidone dimension, independent means to exertsuction on the underside of said conveyer over an area including theprojected area of said perforated portion of the head and extending bothrearwardly and forwardly of said area, the capacity for suction beingsuch as to take in substantiallymore than the amount of; air

fed to said head, whereby in operation fibers are discharged from thehead substantially uniformly in cone centration along said one dimensionof the head and felt on theconveyer'and on the felt being formed thereonand are thereon firmly held by the passing air stream againstmovement-from the line of deposition thereon.

Apparatus for felting comprising a rectangular expans'ion conduitflaring downwardly in both cross-sectional dimensions, means to feedinto the top of said conduit at superatmospheric pressurea suspension inair of material includingfeltable fibers, a perforated rectangular headtion transversely of the axis of the-head; independent 73 closing thelower end of said conduit and exposed ex- 1.1 ternally to theatmosphere, the perforations being arranged for dispersal ofsubstantiallyindividualized fibers therethrough uniformly in one of itstwo rectangular dimensions, agitating means in said head to distributesaid material for dispersal through said perforated head, a movableendless foraminous felting conveyor spaced below. said head and arrangedcontinuously to travel horizontally under said head in a forwarddirection transversely of said one dimension, independent means to exertsuction on the underside of said conveyer over an area including theprojected. area of said perforated portion of the head and extendingboth rearwardly and forwardly of said area, spaced vertical side plates.closing the lateral space between said conveyor and said head fordefining the width of a web to be felted therebetween, and means toregulate the degree of suction locally so as to increase it in thedirection ofmovement' of the conveyer, the

capacity for suction being such as to take in' substantially more thanthe amount of air fed to said head, whereby in operation fibers aredischarged from: the head substantially uniformly in concentration andalong said one dimension of the head and felt with controlled impact onthe conveyer and on the felt being formed thereon and are thereon firmlyheld by the passing air stream against movement from the line ofdeposition thereon.

10. Apparatus for felting comprising a rectangular expansion conduitflaring downwardly in both cross-sectional dimensions, means to feedinto the top of said conduit at superatmospheric pressure a suspensionin air of material. including feltable fibers, a perforated rectangularhead closing the lower end of said conduit and exposed externally to theatmosphere, the perforations being arranged for, dispersal ofsubstantially individualized fibers therethrough uniformly in one of itstwo rectangular dimensions, agitating means in. said head to distributesaid material for dispersal through said perforated head, a movableendless; foraminous felting conveyer spaced below said head and arrangedcontinuously to travel horizontally under. said head in a forward.directi'ontransversely of said one dimension, independent means to exertsuction on the underside of said conveyer over an area including theprojected area of. said perforated portion of the head and extendingboth rearwardly and for.- wardly of said area, and meansto. regulate thedegree of suction locally so as to increase it in the direction. ofmovement of the conveyer, the capacity for suction being such as to takein substantially more than the amount. of air fed to said. head, wherebyinv operationfibers are discharged from the head substantially uniformlyin. CDHCQD: tration and along said. one dimension ofthe head. and feltwith controlled impact on the, conveyer and on the felt being formedthereon and are thereon firmly held by the passingv air stream againstmovement from. the. line of deposition thereon.

11. Apparatus for felting comprising in combination a continuouslymovable endless. foraminous conveyer exposed to atmospheric pressure, asubstantially horizontal open-topped suction box over which the upperstretch of said conveyer is positioned to move, covering means partiallyclosing the opentop of said suctionbox, said means being. variablyperforatedto vary the capacity locally un? der. said conveyer, a blower.having its intake connected tossaid suction box and its. exhaustconnected to a region at atmospheric pressure, a second blower havingits intake connected to a regionat atmospheric. pressure, a. conduitconnected to the outlet of said second blower and arranged at itsterminal, end to discharge substantially vertically downwardly, saidconduit lying in a vertical plane. located so as substantially tobisect-the depositing region of said upper stretchinthe direction: of.itsmovement,. a generally downwardly directed rectangularexe pansion;housingflaring downwardly in both cross-sectional dimensions connectedto and extending from: said conduit, said housing having horizontalrectangular crosssections. symmetrically bisected by said plane asemicylindrical head rounding downwardly as. a bottom closure of saidhousing, said: head having its axis. perpendicular to said plane andbeing'locat'ed. in spaced proximity to and above said conveyer over saidsuction box; parallel vertical side. plates extending from said headsubstantially to said conveyer over the effective. side edges ofthe'suction; box, an arcuate portion ofsaid bottom head havingfiber-dispersing perforations uniformly'in the axial direction extendingto said side plates, the horizontal projection of the perforated areaof. said head on said conveyer. being comprehended within the area ofthe opening of the suction box, and fiber-agitating means in the. head,said head being exposed to the atmosphere whereby independent operationof the. two blowers provides a stream of air'and suspended fiberscrossing the space between said head and said suction; box for feltingfibers on said conveyer when feeding fibers to the intake of said secondblower in. quantity to maintain a supply for agitation in said head. 7

12. Apparatus for felling comprising in combination a continuouslymovable endless foraminous conveyor excharge substantialy verticallydownwardly, saidv conduit" lying in a vertical plane locatedso assubstantially to bisect the depositing region of said upper stretch in.the direction of its movement, a generally downwardly directedrectangular expansion housingflaring downwardly in both cross-sectionaldimensions connected to and ex, tending from saidconduit, saidhousinghaving horizontal. rectangular cross-sectionssymmetricallybisected by said plane, a semi-cylindrical. head roundingdownwardly as a bottom closureof said. housing, said head. having itsaxis. perpendicular to saidv plane and. being, located in spacedproximity to and above said. conveyer. over said. suction box,,parallelvertical side plates extending fromsaid head substantially tosaid'conveyor over theetlective side edges of the suction box, an arcuateportion .oflsai d bottom head having fiber-dispersing perforationsuniformly inthe; axial direction extending to. saidside. plates, thehorizontal pro jectionoftheperforated'area of said head. onsaidcouveyer. being comprehended. within. the. area. of the open-p ing;of; the. suction. box, andfiben-agitating means in. the head,.saidhead.beingexposed-tov the atmosphere whereby independent operationof. the two blowers. provides-a streamof. air and'suspended fiberscrossing thespace be tween saidheadandsaidsuction box for. feltingfibers on.

said. conveyer when feeding fibers. to the-intake of. said secondblowerinquantity to maintain. a supply for. agitation in said head. a a

13.. Apparatus for. felting comprising in. combination. a continuouslymovable endless foraminous conveyer ex, posed to atmospheric pressure, astationaryopen-topped suction box positioned to act on; the. undersidevof said conveyer, a blower having its; intake connected to said suctionbox. and its exhaust connected to aregion at atmospheric pressure,v asecond blower having its intake connected to a region at atmosphericpressure, a conduit connected to the outlet'of said secondblower andarranged at. its terminal. end to. discharge substantially verticallydownwardly, saidconduit'lying in a vertical .plane located so assubstantially to bisect the depositing region of said conveyer in thedirection of its movement, a generally downwardly directed rectangularexpansionhousing. flaring downwardly in both cross-sectional dimensions.connected to and extending. from said conduit, saidhousing havinghorizontal rectangular cross-sections symmetrical.- ly bisected by saidplane, a semi-cylindrical head: rounding downwardly as. a. bottom.closure. 0t said housing, said 13 a a head having its axis perpendicularto said plane and being located in spaced proximity to and above saidconveyer over said suction box, parallel vertical side plates extendingfrom said head substantially to said conveyer over the effective sideedges of the suction box, an arcuate portion of said bottom head havingfiber-dispersing perforations uniformly in the axial direction extendingto said plates, the horizontal .projection of the perforated area ofsaid head on said conveyer beingrcomprehended within the horizontalprojection of the opening of the suction box, and-fiber-agitating meansin the head, said head being exposed to the atmosphere wherebyindependent operation of the two blowers provides a stream of air andsuspended fibers crossing the space between said head and said suctionbox for felting fibers on said conveyer when feeding fibers to theintake of said second blower in quantity to maintain a supply foragitation in said head.

14. Apparatus for felting comprising in combination a continuouslymovable endless foraminous conveyer exposed to atmospheric pressure, asubstantially horizontal open-topped suction box over which the upperstretch of said conveyer is positioned to move, covering means partiallyclosing the open top of said suction box, said means being variablyperforated to vary the capacity locally under said conveyer, a blowerhaving its intake connected to said suction box and its exhaustconnected to a region at atmospheric pressure, a second blower havingits intake connected to a region at atmospheric pressure, aconduitconnected to the outlet of said second blower and arranged at itsterminalend to-discharge substantially vertically downwardly, saidconduit lying in a vertical plane located so as substantially to bisectthe depositing region of said upper stretch in the direction of itsmovement, a generally downwardly directed rectangular expansion housingflaring downwardly in both cross-sectional dimensions connected to andextending from said conduit, said housing having horizontal rectangularcross-sections symmetrically bisected by said plane, a semi-cylindricalhead rounding downwardly as a bottom closure of said housing, said headhaving its axis perpendicular to said plane and being located in spacedproximity to and above said conveyer over said suction box, an arcuateportion of said bottom head having fiber-dispersing perforationsuniformly in the axial direction, the horizontal projection of theperforated area of said head on said conveyer being comprehended withinthe area of the opening of the suction box, and fiber agitating means inthe head, said head being exposed to the atmosphere whereby independentoperation of the two blowers provides a stream of air and suspendedfibers crossing the space between said head and said suction box forfelting fibers on said conveyer when feeding fibers to the intake ofsaid second blower in quantity to maintain a supply for agitation insaid head.

15. Apparatus for felting comprising in combination a continuouslymovable endless foraminous conveyor exposed to atmospheric pressure, asubstantially horizontal open-topped suction box over which the upperstretch of said conveyer is positioned to move, a blower having itsintake connected to said suction box and its exhaust connected to aregion at atmospheric pressure, a second blower having its intakeconnected to a region at atmospheric pressure, a conduit connected tothe outlet of said second blower and arranged at its terminal end todischarge substantially verticallydownwardly, said conduit lying in avertical plane located so as substantially to bisect the depositingregion of said upper stretch in the direction of its movement, agenerally downwardly directed rectangular expansion housing flaringdownwardly in both cross-sectional dimensions connected to and extendingfrom said conduit, said housing having horizontal rectangularcross-sections symmetrically bisected by said plane, a semi-cylindricalhead rounding downwardly as a bottom closure of said housing, said headhaving its axis perpendicular to said plane and being located in spacedproximity to and above said conveyer over said suction 14. box, anarcuate portion of said bottom head having fiberdispersing perforationsuniformly in the axial direction, the horizontal projection of theperforated area of said head on said conveyer being comprehended withinthe area of the opening of the suction box, and fiber-agitating means inthe head, said head being exposed to the atmosphere whereby independentoperation of the two blowers provides a stream of air and suspendedfibers crossing the space between said head and said suction box forfelting fibers on said conveyer when feeding fibers to the intake ofsaid second blower in quantity to maintain a supply for agitation insaid head.

16. Apparatus for felting comprising in combination a continuouslymovable endless foraminous conveyer exposed to atmospheric pressure, asubstantially horizontal open-topped suction box over which the upperstretch *of said conveyer is positioned to move, a blower'havin'g itsintake connected to said suction box and its exhaustconnected to aregion at atmospheric pressure,"a'second blower having its intakeconnected to a region at atmospheric pressure, a conduit connected tothe outlet of said second blower and arranged at its terminal end todischarge substantially vertically downwardly, said conduit, lying in avertical plane located so as substantially to bisect the depositingregion of said upper stretch in the direction of its movement, agenerally downwardly didected rectangular expansion housing fiaringdownwardly in both cross-sectional dimensions connected to and extendingfrom said conduit, said housing having horizontal rectangular crosssections symmetrically bisected by said plane, a perforated head closingthe lower end of said housing located in spaced proximity to and abovesaid conveyer over said suction box, at least an arcuate portion of saidhead having fiber-delivering perforations arranged uniformly in thedirection perpendicular to'said plane, the horizontal projection oftheperforated area of said head on said conveyer being comprehendedwithin the area of the opening of the suction box, and fiber-agitatingmeans in the head, said head being exposed to the atmosphere wherebyindependent operation of the two blowers provides a stream of air andsuspended fibers crossing the space between said head and said suctionbox for felting fibers on said conveyer when feeding fibers to theintake of said second blower in quantity to maintain a supply foragitation in said head.

17. Apparatus for felting comprising in combination a continuouslymovable endless foraminous conveyer exposed to atmospheric pressure, astationary open-topped suction box positioned to act on the underside ofsaid conveyer, a blower having its intake connected to said suction boxand its exhaust connected to a region at atmospheric pressure, a secondblower having its intake connected to a region at atmospheric pressure,a conduit connected to the outlet of said second blower and arranged atits terminal end to discharge substantially vertically downwardly, saidconduit lying in a vertical plane located so as substantially to bisectthe depositing region of said conveyer in the direction of its movement,a generally downwardly directed rectangular expansion housing flaringdownwardly in both cross-sectional dimensions connected and extendingfrom said conduit, said housing having horizontal rectangularcross-sections symmetrically bisected by said plane, a perforated headclosing the lower end of said housing located in spaced proximity to andabove said conveyer over said suction box, at least a portion of saidhead having fiber-dispersing perforations arranged uniformly in thedirection perpendicular to said plane, the horizontal projection of theperforated area of said head on said conveyer being comprehended withinthe horizontal projection of the opening of the suction box, andfiber-agitating means in the head, said head being exposed to theatmosphere whereby independent opera tion of the two blowers provides astream of air and suspended fibers crossing the space between said headand said suction box for felting fibers on said conveyer when feedingfibers to the intake of said second blower in quantity to maintain asupply for agitation in said head.

18. Apparatus for dispersing fibers fo'r felting comprising a conduitfor carrying a stream of air having entrained fibers therein, anelongated expansion chamber flaring in all its cross-sectionaldimensions connected at its small end to' and extending said conduit,said chamber flaring symmetrically with respect to a fixed plane fromits small end to a rectangular opening bisected by said plane, meanshaving a semi-cylindrical shell of a coinciding rectangular opening asits diametrical plane closing the open-end of saidcharnber and extendingoutwardly therefrom with the axis of the cylinder perpendicular to saidfixed plane, an-arcuate portion of said shell between two geometricalelements thereof being perforated symmetrically'with respect to saidfixed plane for the dispersion of fibers therethrough, and a coaxialsquirrel-cage rotor within said shell having elemental bars thereon inclose proximity to the interior of said shell.

' 19. A continuous felting process comprising essentially continuouslysuspending fibers at a substantially constant rate in a constant movingstream of air in a directing conduit, discharging said stream from saidconduit vertically downward in a linear direction and expanding saidstream horizontally in all directions within confining walls to lowerthe velocity, imposing in the path of said expanded stream a perforatedobstacle having less open area than the cross-section of the expandedstream, which obstacle passes the air and oppo'ses free passage of thefibers, forming-and maintaining over said obstacle a gravitated supplyof fibers at an increased concentration, mechanically agitating saidsupply at a level below the top of said supply and simultaneouslymechanically sweeping individualized fibers through the perforations ofsaid ohstacle in the air passing through said perforations, whereby toform a multiplicity of jets of air containing individualized fibers, anddirecting said jets toward a continu ously moving filtering andconveying means having'capacity in operation to pass substantially allthe air from said jets while depositing and conveying away the fibercontents of the jets as a felt.

20. In a felting process, the steps of continuously feeding an expandingstream of air and feltable fibers suspended therein in a downwarddirectio'n and thereby forming and maintaining by gravity a supply of'loose feltable fibers over and on a wall having fiber-passing foramensand in a region of air at superatmospheric pressure, mechanicallyagitating said supply at a level below the top of said supply andsimultaneously mechani-v cally sweeping individualized fibers into saidforamens and discharging fibers through said foramens by the passage ofair through said foramens from the region of said supply, andmaintaining lower pressure on the. op-

posite side of said wall, whereby air flows through saidsupply andthrough said foramens in said wall andcarries fibers therewith.

References Cited in the file of this patent UNITED STATES PATENTS

